The present invention relates to a system providing remote control to medical apparatus, such as a respiratory ventilator for a patient. The system also provides a tactile expression of a parameter relating to a patient or a medical apparatus to a user of the apparatus. For example, the system may provide a tactile indication of a breathing characteristic of a patient connected to a ventilator to a clinician using the system.
In one aspect of the system of the present invention, a manual member has a handle with a moveable, trigger-like member. The handle and trigger are gripped by the user. When the trigger is squeezed by the user, a signal generator is operated to provide a control signal, through a cable or other suitable means, to the ventilator for use in controlling the apparatus. For example, the control signal may be used to control the supply of breathing gases to a patient.
Medical equipment, such as a ventilator, includes sensors providing signals corresponding to various parameters relating to a patient or the apparatus. In another aspect of the invention, a signal corresponding to a parameter, for example patient airway pressure, may be returned, or fed back, from the apparatus to a manual member having a trigger. The feedback signal drives an actuator for the trigger to cause the trigger to exert a force on the fingers of the user that indicates to the user the breathing characteristic of the patient.
In a preferred embodiment of the system, a single manual member is used for both control and feedback purposes.
Respiratory ventilators provide breathing gases to a patient via a breathing circuit. The breathing circuit typically has an inspiratory limb and an expiratory limb. One end of each of the inspiratory and expiratory limbs are connected to the ventilator. The other ends are connected to a Y-connector and through a patient limb to the patient. Pneumatic elements in the ventilator periodically provide breathing gases to the patient through the inspiratory limb during inhalations. On expirations, the breathing gases are discharged from the lungs of the patient into the expiration limb. Controls in the ventilator establish parameters, such as breaths/minute, tidal volume, maximum pressures, etc. that characterize the ventilation provided to the patient by the ventilator.
A patient may also be manually ventilated by means of a flexible container or xe2x80x9cbagxe2x80x9d provided on the ventilator. The bag is filled with breathing gases and manually squeezed by a clinician to provide breathing gases to the patient. Use of the bag, or xe2x80x9cbagging the patient,xe2x80x9d is often required or preferred by clinicians as it enables the clinician to physically control the delivery of breathing gases to the patient. Equally important, the feel of the bag as it is manipulated by the clinician enables the clinician to sense conditions in the lungs and respiration of the patient. In the hands of a skilled clinician, subtle characteristics and/or changes in the lungs and respiration can be sensed. It is difficult or impossible to obtain this type of feedback information when mechanical ventilating apparatus provides the breathing gases.
For the foregoing reasons, patients are often bagged during surgical procedures when anesthesia is induced in the patient by entraining an anesthetic in the breathing gases. Another environment in which patients are often bagged is in an intensive care unit.
However, if bagging is carried out for a long time, it becomes fatiguing to the clinician lessening both the fineness of the control of breathing gas supply and the sensing of lung or other respiratory conditions affecting the subject.
Also, the bag is usually positioned at a fixed location on the ventilator. This restricts the degree to which the clinician, when bagging a patient, can move about the patient, for example, to observe a surgical patient positioned in a manner appropriate to the surgery to be performed. The same is true when the pneumatic elements of the ventilator, rather than the bag, are providing the breathing gases to the patient since the controls necessary to operate the pneumatic elements are placed at a fixed location on the ventilator.
It is, therefore, an object of the present invention to provide a system that enables a clinician, or other user to remotely control medical apparatus, such as a ventilator. The invention may also remotely provide a tactile sensory indication of a parameter, such as a respiratory parameter of a patient connected to a medical apparatus.
The fact that the system is remote, allows the clinician, or other user for the system to move with respect to the apparatus to which the system is connected and with respect to a patient being treated by the apparatus, thereby to improve the effectiveness of care provided to the patient.
In applications involving a respiratory parameter, the system of the present invention provides a control operation and feedback sensation resembling that experienced by a clinician when manually feeling the bag. This enables the clinician to sense and control conditions in the patient in a highly effective manner. However, the system of the present invention avoids the fatigue incurred with manually bagging the patient. The sensing and control provided by the present invention can be enhanced by adjusting the sensitivity and linearity between the control and feedback signals and the resulting control action and tactile sensation generation. This enables an optimal relationship to be established between user input and ventilation delivery for a particular patient.
While the foregoing has described the present invention in connection with sensing ventilation parameters, it may also be used to provide a tactile feedback of other parameters. For example, the system may be used to provide a tactile indication of the cardiac properties, such as blood pressure or pulse rate.
Briefly, the present invention provides a remote feedback system for providing a tactile expression of a characteristic of a parameter of an apparatus to which the system is connected. The apparatus provides a feedback signal indicative of the parameter. The system typically includes a member having a moveable trigger. An electro-mechanical, or fluidic force applying actuator, such as a linear motor, is coupled to the trigger. The feedback signal is provided to the actuator by a communication means, such as a cable or telemetry link. When the member and trigger are gripped by the user, the forces exerted on the fingers of the user by the trigger, as the trigger is driven by the actuator, are an indication of a characteristic of the parameter of the apparatus.
By providing the system with a potentiometer, or other signal generator, operated by the trigger, the system can also provide a signal to control the operation of ventilator apparatus via the communication means.
Various other features, objects, and advantages of the invention will be made apparent from the following detailed description and the drawings.